Golf club head having improved grooves

Abstract

A golf club head is provided, including a planar face with a pattern of horizontal grooves therein each having a cross section with an opening in the planar face. The grooves each include a first side, a second side, a pair of top junctures where the first and second sides join the planar face, a bottom and a pair of bottom junctures where the first and second sides join the bottom. The spacing between the first and second sides continually increases from the bottom to the top junctures. Each of the sides includes a lower section positioned nearer the bottom and an upper section positioned nearer the face. Each of the lower and upper sections is substantially planar. The top junctures are convexly rounded and the bottom junctures are concavely rounded.

We claim:  
     
       1. A golf club head including a planar face with a pattern of horizontal grooves therein, each of said grooves defining an opening in the planar face and including a first side, a second side, a pair of top junctures where said first and second sides join said planar face, a bottom, and a pair of bottom junctures where said first and second sides join said bottom, a spacing distance between said first and second sides continuously increasing from said bottom junctures to said top junctures, said first side being substantially a mirror image of said second side, each of said sides having a lower section positioned adjacent to said bottom and an upper section positioned adjacent to said face, each of said lower and upper sections being substantially planar, an angle formed by planes that are co-planar with said upper sections and extending downward therefrom having a measurement greater than an angle formed by planes that are co-planar with said lower sections and extending downward therefrom, each of said top junctures being concavely rounded, each of said bottom junctures being concavely rounded, a middle juncture being defined between each of a pair of adjacently positioned upper and lower sections, each of said middle junctures being convexly rounded. 
     
     
       2. A golf club head as defined in  claim 1 , wherein said angle formed by said planes that are co-planar with said lower sections is between about 5 degrees and about 40 degrees, and said an angle formed by said planes that are co-planar with said upper sections is between about 80 degrees and about 100 degrees. 
     
     
       3. A golf club head as defined in  claim 1 , wherein each of said top junctures is defined by a first radius of curvature that is constant. 
     
     
       4. A golf club head as defined in  claim 3 , wherein said first radius of curvature is between about 0.10 mm and about 0.30 mm. 
     
     
       5. A golf club head as defined in  claim 3 , wherein each of said bottom junctures is defined by a second radius of curvature that is constant. 
     
     
       6. A golf club head as defined in  claim 5 , wherein said second radius of curvature is between about 0.10 mm and about 0.50 mm. 
     
     
       7. A golf club head as defined in  claim 5 , wherein each of said middle junctures is defined by a third radius of curvature that is constant. 
     
     
       8. A golf club head as defined in  claim 7 , wherein said third radius of curvature is between about 0.06 mm and about 0.25 mm. 
     
     
       9. A golf club head as defined in  claim 1 , wherein each of said grooves has a depth, measured from said planar face to said bottom, greater than about 0.37 mm. 
     
     
       10. A golf club head as defined in  claim 1 , wherein: 
       each of said top junctures has a width between about 0.18 mm and about 0.21 mm;  
       each of said bottom junctures has a width between about 0.31 mm and about 0.35 mm; and  
       each of said middle junctures has a width between about 0.05 mm and about 0.09 mm.  
     
     
       11. A golf club head as defined in  claim 10 , wherein: 
       each of said upper sections has a length between about 0.07 mm and about 0.03 mm;  
       each of said lower sections has a length between about 0.09 mm and about 0.05 mm; and  
       each of said bottoms has a width between about 0.08 mm and about 0.04 mm.  
     
     
       12. A golf club head as defined in  claim 1 , wherein each of said grooves has a width between about 0.70 mm and about 0.86 mm, the width of said groove being measured along a line extending between a pair of tangents points of a pair of oppositely spaced lines each being at a 30-degree tangent to one of the upper junctures of said groove. 
     
     
       13. A golf club head as defined in  claim 1 , wherein said grooves are spaced apart from each other by a distance in the range of about 3.3 mm to about 3.4 mm, taken from lines bisecting a pair of adjacently positioned grooves. 
     
     
       14. A golf club head as defined in  claim 1 , wherein the grooves are formed in the planar face by CNC milling. 
     
     
       15. A golf club head as defined in  claim 2 , wherein: 
       each of said top junctures is defined by a first radius of curvature that is constant;  
       each of said bottom junctures is defined by a second radius of curvature that is constant; and  
       each of said middle junctures is defined by a third radius of curvature that is constant.  
     
     
       16. A golf club head as defined in  claim 15 , wherein the grooves are formed in the planar face by CNC milling. 
     
     
       17. A golf club head including a planar face with a pattern of horizontal grooves therein, each of said grooves having an opening in the planar face and including a first side, a second side, a pair of top junctures where said first and second sides join said planar face, a bottom, and a pair of bottom junctures where said first and second sides join said bottom, a spacing distance between said first and second sides continuously increasing from said bottom to said top junctures, each of said sides including a lower section positioned adjacent to said bottom and an upper section positioned adjacent to said face, each of said lower and upper sections being substantially planar, each of said top junctures being convexly rounded, and each of said bottom junctures being concavely rounded; 
       wherein an angle formed by planes that are co-planar with said upper sections and extend downward therefrom is greater than an angle formed by a pair of planes that are co-planar with said lower sections and extend downward therefrom.  
     
     
       18. A golf club head as defined in  claim 17 , wherein a middle juncture is defined between each of a pair of adjacent upper and lower sections, each of said middle junctures being convexly rounded. 
     
     
       19. A golf club head as defined in  claim 18 , wherein: 
       each of said top junctures is defined by a circular arc having a first radius and is tangent to said planar face and the adjacent upper section;  
       each of said bottom junctures is defined by a circular arc having a second radius and is tangent to said bottom and tangent to the adjacent lower section; and  
       each of said middle junctures is defined by a circular arc having a third radius and is tangent to the adjacent upper and lower sections.  
     
     
       20. A golf club head as defined in  claim 17 , wherein the grooves are formed in the planar face by CNC milling. 
     
     
       21. A golf club head as defined in  claim 17 , wherein: 
       each of said top junctures is defined by a circular arc having a first radius and is tangent to said planar face and tangent to the adjacent upper section; and  
       each of said bottom junctures is defined by a circular arc having a second radius and is tangent to said bottom and tangent to the adjacent lower section.  
     
     
       22. A golf club head as defined in  claim 21 , wherein the grooves are formed in the planar face by CNC milling.